A easy way to shorten it would be just to test the variables against eachother. If number1 is equal to number2 and number2 is equal to number3 that means there was a winner. Then you can just print whatever number is in them variables to tell the user how much they have won.

First, number1==number2 are compared. This results in a true or false boolean result. This result is then compared to number3, again resulting in a bool result. This bool result is then compared to the number 1.